Biological Diversity Topic 6 The Best Selection

Do you have a cat or a dog at home? Do you own a pet rabbit? –These animals are considered Domestic.

The Best Selection Domestic Animal: –An animal that is no longer wild, but has been bred or tamed by humans to perform various functions. –Ex. Cows for milk and meat, chickens for eggs and meat, horses and donkey for labour etc.

The Best Selection Artificial Selection / Selective Breeding: –Technique in which individual plants or animals with desirable traits are bred together to develop plants or animals with specific traits –Artificial selection has been used by people for thousands of years to produce domestic plants and animals with particular characteristics

The Best Selection Ex. Corn used to be purple with only 12 kernels per cob Ex. Carrots used to be smaller and purple and were bred to be large and orange by the Dutch Ex. Horses used to be too small to carry us

Artificial Selection in Agriculture Our ancient hunter-gatherer ancestors began planting wheat and barley seeds as a reliable food source around years ago in the fertile crescent (modern day Iraq)

Artificial Selection in Agriculture Though wheat was domesticated during prehistoric times, both wheat and rice now make up 40% of the human population’s energy supply

Artificial Selection in Agriculture Selective Breeding: –Also known as Artificial Selection –Selective Breeding has allowed many cultures around the world to create new and more useful food crops

Artificial Selection in Agriculture In Canada Wheat crops such as “Western Red Spring Wheat” was created through selective breeding because its flour is good for making pan bread

Artificial Selection in Agriculture Other forms of wheat were created for other functions such as “Canadian Western Amber Durum” wheat whose flour is good for making pasta

Artificial Selection in Agriculture Researchers are also concerned with which wheat will grow in which climate and selectively breed wheat to grow in these areas

Artificial Selection in Agriculture Other selective breeding programs create wheat varieties that are resistant to insects and disease etc. Dr. Ohm - Wheat breeding Rust Resistant Durum Wheat

Accounting for Biological Diversity Charles Darwin is one of the most famous biologists of all time due to his theory of Natural Selection

Accounting for Biological Diversity Darwin came up with his idea after taking a voyage on the H.M.S. Beagle to the Galapagos islands off the coast of South America in 1831

Accounting for Biological Diversity While in the Galapagos, Darwin recognized that there were a variety of Finches (a small bird) on the islands, each with different adaptations that allowed them to feed on different food sources avoiding competition with each other

Accounting for Biological Diversity He realized that these adaptations due to competition were caused by natural pressures put onto the Finches by their environment A look at the finches of the Galapagos islands

Accounting for Biological Diversity When the Beagle returned to England, Darwin published his famous book called the “Origin of Species by Means of Natural Selection” in 1859 changing the way that Biologists viewed the world forever

The Theory of Natural Selection Natural Selection: –A naturally occurring process in which only those organisms with the best traits for survival in an environment survive to reproduce. –Over time this process results in changes in the genetic characteristics of a species.

The Theory of Natural Selection The theory of natural selection can be summed up in four statements: 1.All organisms produce more offspring than can possibly survive 2.There is incredible variation within each species 3.Some of these variations increase the chances of an organism surviving to reproduce 4.Over time, variation that are passed on lead to changes in the genetic characteristics of a species. –Evolution Primer #4: How Does Evolution Really Work?Evolution Primer #4: How Does Evolution Really Work?

The Theory of Natural Selection Ex. The Giraffe The ancient ancestors of the Giraffe had short necks As food became scarce, those Giraffe ancestors with slightly longer necks (a natural variation) were able to eat food from taller trees These Giraffe ancestors were able to survive better and mate more often

The Theory of Natural Selection Ex. The Giraffe cont’d Their offspring had slightly longer necks and due to variation some of the offspring had naturally longer necks than their siblings These Giraffe ancestors were able to survive better and mate more often passing on their genes to the next generation After millions of years and countless generations the necks of Giraffes became as long as they are today

The Theory of Natural Selection Ex. The Giraffe cont’d **Note: As the Giraffe evolved to have a longer neck, the trees that they fed on also evolved to be taller so that they weren’t eaten and killed by Giraffes. This is called co-evolution

The Theory of Natural Selection Ex. The Peppered Moth –There are two varieties of the peppered moth in England, a light colour and a dark colour –The light coloured peppered moth was the most common as it easily camouflaged with the trees it sat on and therefore was not eaten

The Theory of Natural Selection Ex. The Peppered Moth cont’d –During the industrial revolution trees in England began to turn black with soot –The less common black peppered moth was able to camouflage better and thus survived better and was able to mate more, passing on its genes to the next generation –The black peppered moth then became more common than the white peppered moth –Evolution of the Peppered MothEvolution of the Peppered Moth